The early explorations are mainly developed from the atmospheric scattering model [1]}, [2]}, [3]}, [4]}, which formulates the haze-free image as an analytic solution with three variables, i.e., haze image, transmission map and atmospheric light. Then, various prior assumptions are proposed to estimate the transmission map or atmospheric light, such as dark channel [5]}, color attenuation [6]}, boundary constraint [7]} and so on. Limited by aforementioned specific assumptions, these prior based methods hardly perform well under diverse hazy scenes.
